We look at the division of 77605032 by 309 
The aim is to understand the frequency of 309 in 77605032.

On to step 1:
The number 309 fits into 7 0 times, leaving a remainder of 7.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 7, we get 7.
Append the next digit (7) from the dividend to 7 and continue with: 77 / 309

Going ahead to step 2:
309 can be fit into 77 0 times, resulting in a remainder of 77.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 77, we get 77.
Take the next digit (6) from the dividend and append it to 77, then repeat: 776 / 309

Step 3:
If we divide 776 by 309, we get 2 and a remainder of 158.
Record the quotient 2 as the next digit in the result. 
Result so far: 2.0
If we subtract 618 from 776, we get 158.
Take the next digit (0) from the dividend and append it to 158, then repeat: 1580 / 309

On to step 4:
When dividing 1580 by 309, we get 5 with a remainder of 35.
Record the quotient 5 as the next digit in the result. 
Result so far: 25.0
The remainder is 35 after subtracting 1545 from 1580.
Append the next digit (5) from the dividend to 35 and continue with: 355 / 309

On to step 5:
If we divide 355 by 309, we get 1 and a remainder of 46.
The number 1 becomes the next digit in our result. 
Result so far: 251.0
Deduct 309 from 355 and we're left with 46.
Include the next digit (0) from the dividend after 46, then repeat: 460 / 309

Let's proceed to step 6:
309 goes into 460 1 times with a remainder of 151.
Record the quotient 1 as the next digit in the result. 
Result so far: 2511.0
If we subtract 309 from 460, we get 151.
Take the next digit (3) from the dividend and append it to 151, then repeat: 1513 / 309

On to step 7:
309 goes into 1513 4 times with a remainder of 277.
The number 4 becomes the next digit in our result. 
Result so far: 25114.0
Subtracting 1236 from 1513 leaves us with 277.
Append the next digit (2) from the dividend to 277 and continue with: 2772 / 309

On to step 8:
309 can be fit into 2772 8 times, resulting in a remainder of 300.
Put 8 as the next digit of the answer. 
Result so far: 251148.0
The remainder is 300 after subtracting 2472 from 2772.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3000, and continue the process.

Advancing to step 9:
309 can be fit into 3000 9 times, resulting in a remainder of 219.
The next digit of our result is 9. 
Result so far: 251148.9
Subtracting 2781 from 3000 leaves us with 219.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2190, and continue the process.

Advancing to step 10:
2190 divided by 309 is 7 with a remainder of 27.
Use 7 as the next digit of our solution. 
Result so far: 251148.97
If we subtract 2163 from 2190, we get 27.
Since there are no more digits in the dividend, we add a zero to the remainder making it 270, and continue the process.

Step 11:
If we divide 270 by 309, we get 0 and a remainder of 270.
Put 0 as the next digit of the answer. 
Result so far: 251148.97
Subtracting 0 from 270 leaves us with 270.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2700, and continue the process.

Going ahead to step 12:
If we divide 2700 by 309, we get 8 and a remainder of 228.
The number 8 becomes the next digit in our result. 
Result so far: 251148.9708
Subtract 2472 from 2700 to get 228.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2280, and continue the process.

Going ahead to step 13:
309 can be fit into 2280 7 times, resulting in a remainder of 117.
Put 7 as the next digit of the answer. 
Result so far: 251148.97087
Deduct 2163 from 2280 and we're left with 117.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1170, and continue the process.

Going ahead to step 14:
309 goes into 1170 3 times with a remainder of 243.
The number 3 becomes the next digit in our result. 
Result so far: 251148.970873
Subtracting 927 from 1170 leaves us with 243.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2430, and continue the process.

Step 15:
The number 309 fits into 2430 7 times, leaving a remainder of 267.
The number 7 becomes the next digit in our result. 
Result so far: 251148.9708737
If we subtract 2163 from 2430, we get 267.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2670, and continue the process.

Step 16:
309 goes into 2670 8 times with a remainder of 198.
Write down 8 as next digit of the result. 
Result so far: 251148.97087378
If we subtract 2472 from 2670, we get 198.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1980, and continue the process.

After the division, we end up with 251148.97087378 and a remainder of 1.98e-07.